The drugs, all available in generic form, appear to block formation of sticky wads of protein called amyloid plaques that build up in brains of Alzheimer's patients. Caffeine and fish oil were found to reduce the plaques in animals, scientists said at the Society for Neuroscience meeting in San Diego.
As people live longer and the number of Alzheimer's cases increases, drugmakers are investing billions of dollars to develop new treatments. If widely available medicines and substances such as fish oil and caffeine help, that could ease the suffering and prolong the independence of millions of elderly people, researchers said at the meeting.
"If you delay Alzheimer's by only five years without increasing life span, you could cut the number of cases in half," said Eric Reiman, director of the Banner Alzheimer's Institute in Phoenix, in an interview at the conference. "And it's possible you could do even better than that." Reiman was not involved in the research.
About 5.1 million Americans have Alzheimer's, which damages memory and mental abilities. That may rise to between 11 million and 16 million by 2050, says the Chicago-based Alzheimer's Association, a research and advocacy group. Now, someone develops Alzheimer's every 72 seconds; by mid-century, it will be every 33 seconds, the association estimates.
Drugs that lower blood pressure have been tested as possible treatments for Alzheimer's before with conflicting results. To settle the question, researchers at Mount Sinai School of Medicine in New York screened 55 blood pressure drugs.
The scientists, led by Giulio Pasinetti, extracted amyloid proteins from mice that are genetically engineered to have a form of Alzheimer's and mixed them with the drugs. Seven of the medications caused a reduction of the amyloid proteins in the test tube and three of those, given to living mice with Alzheimer's, cut the number of plaques in their brains.
The three medications include Coreg, now sold in generic form as carvedilol, and the Roche drugs, sold generically as propranolol and nicardipine. These medicines cut the plaque when used in doses far lower than those prescribed to reduce blood pressure. That may mean they won't cause unwanted lowering of blood pressure, Pasinetti said at the conference.
Pasinetti said the drugs may work by increasing blood flow and sweeping the amyloid proteins out of the brain before they can accumulate and form plaques. He hopes to begin soon small safety studies followed by larger clinical trials of the three drugs in people with Alzheimer's, he said.
Fish oil and its key ingredient, omega-3 fatty acids, found in fatty fish like salmon, are a mainstay of alternative health practitioners and have been endorsed by the American Heart Association to reduce the risk of cardiovascular disease.
The oil also shows promise for preventing Alzheimer's, said Gregory Cole, a neurologist and associate director of the Alzheimer's Disease Research Center at the University of California, Los Angeles. Data from the 50-year, government-run Framingham Heart Study show that "people with higher levels of fish oil had half the levels of Alzheimer's," Cole said.
Cole and his colleagues have conducted studies that suggest that higher levels of fish oil reduce plaque formation in Alzheimer's mice. A new study, presented at the Neuroscience conference, suggests a possible mechanism. It found that fish oil cuts levels of another protein that assists the sticky amyloid proteins to accumulate.
Five Cups of Coffee
Then there is caffeine. Gary Arendash, a researcher at the Byrd Alzheimer's Institute in Tampa, Florida, says giving Alzheimer's mice the human equivalent of five cups of coffee, or 500g of caffeine, a day also has plaque-busting effects and reverses symptoms of impaired memory in aging Alzheimer's mice.
He presented data at the conference that show caffeine can reduce levels of two enzymes that play a role in the complex process of amyloid plaque formation.
"I don't know of any drug under development that can address and suppress both of these enzymes," Arendash said.
If preventing Alzheimer's was as easy as drinking coffee, why do so many elderly Americans develop the disease, asked Arendash. The average American drinks only 150mg of coffee a day and reduces intake with age, he said.
His institute recently started clinical trials of caffeine in older people to see whether a few cups of coffee also prevent or treat Alzheimer's. Arendash seems to know the answer already.
"Caffeine could be a surprisingly effective treatment against this disease," he said. "It's almost too good to be true."
From the November 19, 2007, Prepared Foods e-Flash